Conventional transmittance variable film is activated by a polymer dispersed liquid crystal (PDLC) or an electrochromism (EC). In PDLC film, an encapsulated liquid crystal is present in a polymer and the reflectance and transmittance is adjusted by controlling the orientation of the crystal by an electric field. In EC film, the transmittance is adjusted using a material whose color is changed by an electric field. With recent increase of interests in a variety of display devices and functional glasses, there is an increasing trend in interests for a transmittance variable film with a high performance and high energy efficiency.